[The compliance-volume relationship in healthy persons and in cases of fibrosis of the lungs and pulmonary emphysema (author's transl)].

An analysis of the expiratory quasi-static compliance over the whole range of the vital capacity shows that there is a certain range over which compliance is optimal. Compliance-volume relationships were determined in 14 healthy subjects, in 25 persons with fibrosis of the lungs and in 17 cases of obstructive pulmonary emphysema. The volume of the plateau on the compliance curve shows a close relationship with the vital capacity. In persons with pulmonary fibrosis there is a decrease not only of compliance but also of the plateau volume. Their tidal air volume is decreased and amounts to 50 per cent of the plateau volume. In healthy persons the tidal air volume is significantly larger. It amounts to only 23 per cent of the plateau volume. The latter, together with the lung compliance, provides a satisfactory explanation for the decreased ventilatory reserves in patients with fibrosis of the lungs. Although the volume of tidal air is increased in persons with obstructive pulmonary emphysema, as compared with normal subjects, it amounts to 32 per cent of the plateau volume even during quiet breathing.